Team USA stayed warm during  the opening day of the Olympic ceremonies, wearing self-heating, battery-powered parkas. How do they work and who’s behind the technology?

The opening ceremony of the Olympics centered on a message of peace, passion, harmony and convergence. The delegations from both the host nations, South Korea and North Korea, marched under the Korean unification flag.

Even though the temperatures were bitter cold, Bermuda’s delegation wore shorts and Tongan Pita Taufatofua went shirtless, again oiled up as he entered the Olympic stadium waving his country’s flag.

Team USA, while cold-conditioned, opted to stay warm during the opening ceremonies wearing water-repellent, fully washable, down-filled jackets featuring the American flag printed on the inside back of the jacket, shown in Today’s post.

The genius behind the jacket is in the conductive ink used to create the U.S. flag. A removable, rechargeable battery—stored in a pocket—plugs into the jacket and heats up the flag. With three different power settings, the flag will stay warm for up to 11 hours when set on the lowest setting.

“Key to ConnexI/O is our ‘snap-and-latch’ technology, which allows our connector to be integrated on the apparel factory floor, requiring no soldering, opening up new opportunities for the seamless integration of electronics into a variety of e-textile substrates.” – Principled Design

Polo Ralph Lauren is the branded name on the jacket, but the jacket is a collaboration between many design and manufacturing firms based in the U.S.A. and it’s this collaboration–just like Team USA– that makes the jacket an Olympic Gold winner.

The jacket sold out immediately at $2,495, but you can buy it on eBay if you’re willing to pay up to six times the original selling price. The jacket will be sold exclusively through Polo Ralph Lauren’s NYC Soho store.